N-(4-Hydroxyphenyl)-all-trans-retinamide, also known as HPR or fenretinide and having CAS registry number 65646-68-6, is described in U.S. Pat. Nos. 4,190,594 and 4,323,581 and has the following formula: ##STR2## HPR protects against mammary cancer in rats induced with N-nitroso-N-methyl urea, and is less toxic when given orally to rats then retinyl acetate and retinoic acid, see R. C. Moon et al. in Cancer Research, Vol. 39, pages 1339-1346 (1979). When given to rats, one formulation of HPR (5 mg/kg) was incompletely absorbed after oral administration and was eliminated slowly with a half-life of 12 hours, see B. N. Swanson et al. in Drug Metababolism Disposition, Vol. 8 No. 3, pages 168-172 (1980).
In the experimental treatment of cancer described in U.S. Pat. No. 4,323,581, HPR is dissolved in a thioctanoin:ethanol (3:1), Tenox 20 and DL-.alpha.-tocopherol solvent system which is then mixed with lab meal. Thus, the HPR is administered by admixture with the diet. HPR is virtually insoluble in water and also quite expensive; administration of tablets or aqueous suspensions of HPR would require ingestion of large quantities of HPR to achieve resonable blood levels of the drug. Efficient administration of pharmaceutically effective levels of HPR to patients is a recognized goal.
The biopharmaceutics of griseofulvin was studied by Philip J. Carrigan in the Journal of Pharmaceutical Sciences, Vol. 62, No. 9, pps. 1476-1479 (1973) wherein an aqueous suspension, a corn oil suspension with polysorbate 60 and a three-phase oil-in-water emulsion containing polysorbate 60, corn oil and water were evaluated. The use of suspensions including vegetable oils and surface active agents for soft gelatin capsules is described at page 371 of "The Theory and Practice of Industrial Pharmacy" Ed. by Leon Lachman, Lea & Febiger, Philadelphia, PA (1970).